Hello fellow HAMBers I am collecting parts for a new project. Trying to learn about figuring rear end ratio and final drive. I did a little research and read that for a street rod application a final drive ratio <10 is ideal. Here is the parts I have so far: T5 trans with following gears 1st 3.97, 2.34, 1.48, 1.00, 0.79 Rear axle is a Ford banjo I have 3:78 and 4:11 gears... but thinking the 3:78 would be best. I have no gears for the quick change yet. Car will be lighter under 2500lbs, 302 Ford motor with around 300 HP I am thinking about running 7.50 tall tires in the rear. So how do I figure this all out? I have read some pages about finding final drive by multiplying the trans gear by the rear. For 1st gear this would be 3.97x3.78=15 which is well above that ideal 10 or less. Is this too low for a street rod application? Also where is a good starting point for quick change gears. Thanks in advance!
Does that "less than 10" thing apply to 5 speed transmissions? or is it more for older 3 or 4 speeds? Did you think about shopping around for a closer ratio transmission? sounds like you have a trans that was meant for a small engine car, if you get one from a higher perf car it will have closer ratios 1-4 and a taller overdrive. http://www.allfordmustangs.com/Detailed/349.shtml 3.78 does sound like a good starting ratio. you can play with the quick change if you don't like it. Don't worry about it, just build it and later on buy a few gear sets to play with.
Yeah. Just start with a set #1. 24 teeth on both change gears.Or #3 and have a 4.11 or 3.48. Should be good.
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